Error Probability Evaluation for RAKE Reception of DS-CDMA Signals with MRC and EGC Combining in Rayleigh Fading

The RAKE correlator is a digital receiver for DS- CDMA signals that takes advantage of the autocorrelation properties of the spreading/scrambling sequences in order to resolve and efficiently combine the multipath received components in order to increase the average received signal to noise ratio (SNR). Assuming slow, selective, uncorrelated Rayleigh fading with an equally spaced exponential power delay profile, a decision aided (DA) scheme is proposed in order to estimate the complex channel coefficients needed for coherent combining. Monte Carlo simulations are carried out to comparatively assess the performance of maximal ratio combining (MRC) and equal gain combining (EGC) RAKE reception. Channel estimation using the UMTS downlink primary common pilot channel (P-CPICH) is discussed. Thus, the rough estimates resulted after descrambling the corresponding signal are further refined by way of the above mentioned DA scheme.